arc-mcp

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It discloses behavioral traits such as the hierarchical output and inclusion of pinned/unpinned sections, but it lacks details on permissions, rate limits, or response format. The description adds some context but is incomplete for a tool with no annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is appropriately sized with two sentences that are front-loaded and efficient. Each sentence adds value: the first states the purpose and scope, and the second specifies the output details, with zero wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's low complexity (1 optional parameter, no output schema, no annotations), the description is reasonably complete. It explains what the tool does and the output structure, but it could benefit from more behavioral details (e.g., error handling or default behavior) to be fully comprehensive.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents the single parameter 'space' with its description. The description does not add any additional meaning or details about the parameter beyond what the schema provides, resulting in a baseline score of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the specific action ('List tabs and folders'), the resource ('in an Arc browser space'), and the scope ('with full hierarchy'). It distinguishes from siblings like 'list_spaces' (which lists spaces, not tabs) and 'add_tab' (which adds rather than lists).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage by specifying the context ('in an Arc browser space') and what it shows ('pinned and unpinned sections with nested folders'), but it does not explicitly state when to use this tool versus alternatives like 'list_spaces' or provide exclusions. The guidance is contextual but not explicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.